Disorder-induced changes of superconducting Tc obtained by low-temperature ion irradiation of simple metals and alloys

• Published in: Physical review. B, Condensed matter Condensed matter, 1992, Vol.45 (2), p.895-906
• Main Authors: MIEHLE, W, GERBER, R, ZIEMANN, P
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Physics; Properties of type I and type II superconductors; Superconductivity
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/PhysRevB.45.895

By applying low-temperature (T < 10K) ion irradiation to continuously increase the disorder of Zn, Al, alpha -Ga, beta -Ga, indium, Pb, AuIn2, and Al2Au films, the corresponding relative changes of the superconducting transition temperature delta t = Delta Tc/Tc0 were studied as a function of the electrical resistivity rho . In all cases, a linear delta t-vs.- rho relation is observed over a wide range of resistivities. The corresponding slopes ( delta t/ rho ) are compared to existing theories and good agreement is found, provided that experimental input parameters are used for the calculations. For Al, by ion-bombarding oxygen-containing films, the influence of these impurities on the value of ( delta t/ rho ) could be demonstrated. In addition, by repeating vapor-quenching experiments onto liquid-helium-cooled substrates for Zn, alpha -Ga, and Al, earlier discrepancies concerning the value of ( delta / rho ) are resolved. Even in cases in which an amorphous phase results by ion irradiation ( alpha -Ga, AuIn2, Al2Au), a continuous delta t-vs.- rho curve is obtained, emphasizing a universal behavior of Tc on disorder. A detailed comparison of disorder produced by different preparation techniques clearly reveals deviations from such universality. This indicates that different types of defects act differently on Tc.